Well pump device

ABSTRACT

A well pump device, especially for use in connection with the recovery of hydrocarbons, wherein the pump is carried to a predetermined position within a well pipe. The pump is provided with an external seal which is arranged to prevent fluid from flowing from the pressure side of the pump past the pump to the suction side thereof.

BACKGROUND OF THE INVENTION

This invention relates to a well pump in particular for use in a well inconnection with the recovery of hydrocarbons.

SUMMARY OF THE INVENTION

In recent years the development in the drilling technology for therecovery of petroleum has steadily moved in the direction of moredeviation drilling, which means that from a drilling station wells canbe drilled to petroleum deposits located at a considerable horizontaldistance from the drilling station.

Such drilling involves that the pipe angle in the well strongly deviatesfrom the vertical direction. In some cases the well may be approximatelyhorizontal.

It is often necessary to place a pump in the well in order to increasethe pressure or pump fluid up. Conventionally, the pumps have beenpositioned by being lowered into the well by means of gravity in orderthen to be pulled back up by means of a line or similar attached to thepump. The pump delivers the fluid through a connected pressure pipe orhose. In wells that have a large angular deviation relative to thevertical axis, the pump must be pushed forward to its predeterminedposition in the well. This may be accomplished by the use of a so-calleddrive plug. The drive plug is a device adapted for transportingequipment internally in pipes. It may be provided with seals that sealagainst the inner wall of the pipe, and is, in that case, pushed backand forth within the pipe by means of the pressure difference in thepipe. Another type of drive plug is provided with driven wheels orbelts, which carry the plug in the desired direction through contactwith the pipe wall.

Drive plugs based on propulsion by means of differential pressurenormally have the greatest pull-thrust-force, and are therefore oftenused when relatively large loads are to be transported.

The use of such plugs, which must be pulled out of the well after thepump has been installed, represents a great risk of damage to the powerand instrument cable of the well pump. To position an often longpressure pipe from the pump up to the surface is expensive andlabour-intensive.

The object of the invention is to remedy the drawbacks of knowntechniques/devices that make use of a drive plug and a separate pressurepipe/hose.

The object is realized according to the invention through the featuresspecified in the description below.

An electrically or hydraulically operated pump of a kind known initself, comprising a motor, a suction screen/inlet, a pump housing, oneor more pump stages, outlet and connected cables or pipes/hoses for thesupply of energy and control, is provided with an external seal whichseals against the internal wall of the pipe. The pump is provided withcentralizing devices, which keep the pump centred in the pipe. The pumpmay further be provided with a valve/blocking device which may shut offthe flow of fluid through the pump.

When the pump is to be used, it is inserted into the well pipe in thesame way as a differential pressure drive plug. Because the passagethrough the pump is closed and the external seal is sealing against thewall of the well pipe, fluid cannot get past the pump.

The position of the pump in the well can be determined by, for example,previously mounted stops or a seat in the well pipe, or in that the pumpis retained by a line or reinforced cable/hose attached to the pump.

After the passage has been opened and the pump started, the pumpdelivers fluid from one side of the pump to the other side, thus usingthe well pipe as a pressure pipe. The external seal against the wall ofthe well pipe prevents the fluid from returning past the pump.

A development of the pump may be to adapt it for use in tanks and othercontainers to which access is difficult, but where there are premountedaccess pipes or similar.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following a non-limiting example of a preferred embodiment isdescribed, and it is visualized in the accompanying drawings, in which:

FIG. 1 shows, partly in section, the pump mounted in a well pipe;

FIG. 2 shows a section through the pump and the well pipe at thecentralizing devices.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIG. 1 the reference numeral 1 identifies an electrically orhydraulically driven pump comprising a motor 2, a suction screen/inlet3, a pump housing 4, which may be provided with one or more pump stagesnot shown, an outlet 5 and an attachment bearing 6 for connected cablesor pipes/hoses 7 for the supply of energy and control of the pump. Thepump 1 is provided with an external seal 8, which seals against theinternal wall surface of a well pipe 10, and a centralizing device 9,which keeps the pump centred within the pipe. The centralizing devicemay comprise three or more resilient bows secured to the motor housing 2and arranged to press resiliently against the internal wall of the pipe10. The pump 1 may further be provided with a valve 11 or a blockingdevice of a kind known in the art, which may shut off the flow of fluidthrough the pump 1.

When the pump 1 is to be used, it is inserted into the well pipe 10. Theinternal valve 11 is closed, thereby sealing against fluid passagethrough the pump housing 4. The external seal 8 seals against theinternal surface of the well pipe 10. The pump 1 thus seals against thewell pipe 10 in the same way as a drive plug and may be carried forwardto the desired position in the well by means of differential pressurewithin the pipe.

The position of the pump 1 in the well pipe 10 may be predetermined, forexample by a previously installed (not shown) stop in the well pipe 10,or in that the pump 1 is retained by a line or reinforced cable/hose 7attached to the pump 1 in the attachment bearing 6.

Energy is supplied to the motor 2 through the cable/hose 7. When thevalve 11, which may be a butterfly valve, and which may close to fluidflow through the pump, is opened, for example in that the current forthe motor 2 is also connected to the valve 11, and the motor 2 isstarted, fluid will enter through the annular gap 12 which is formedbetween the well pipe 10 and the motor 2, through the suctionscreen/inlet 3 and further to not shown pump stages in the pump housing4. From the pump housing 4 the fluid exits through the outlet 5 into thewell pipe 10 on the pressure side of the pump 1 and further through thewell pipe 10. The fluid on the pressure side of the pump 1 is preventedfrom returning between the pipe 10 and the pump 1 by the seal 8.

A device according to the invention remedies the main drawbacks ofconventional equipment in that it eliminates the need both for aseparate drive plug to be used to position the pump, and for a separatepressure pipe to be used for the transport of the fluid out of the wellpipe.

1. A well pump device for use in connection with the recovery ofhydrocarbons comprising: a pump device including a fluid inlet and afluid outlet, wherein the pump device is adapted to intake fluid throughthe fluid inlet and to output fluid through the fluid outlet; a sealassembly adapted to interface with an interior surface of a well pipe tofrom a seal between the well pipe and the seal assembly such that thepump device may move through the well pipe while the seal assemblyinterfaces with the interior surface of the well pipe, wherein the fluidinlet is located on a first side of the seal assembly and the fluidoutlet is located on a second side of the seal assembly; and a valvethat alternately: places the fluid inlet in fluid communication with thefluid outlet; and removes the fluid inlet from fluid communication withthe fluid outlet to enable the formation of a pressure differencebetween the sides of the seal assembly; wherein the well pump device isadapted to be moved through the well pipe by the pressure differencewhen the valve has removed the fluid inlet from fluid communication withthe fluid outlet and adapted to pump fluid from the fluid inlet out thefluid outlet when the valve has placed the fluid inlet in fluidcommunication with the fluid outlet.
 2. A well pump device according toclaim 1, further comprising centralizing devices adapted to keep thepump device centered in the well.
 3. A well pump device according toclaim 1, wherein the valve is a butterfly valve.
 4. The well pump deviceof claim 1, wherein the well pump device is further adapted to pumpfluid through the outlet to be in direct contact with the well pipe whenthe valve places the fluid inlet in fluid communication with the fluidoutlet.
 5. A combination well pump/well drive plug device for use inconnection with the recovery of hydrocarbons comprising: a pump deviceincluding a fluid inlet and a fluid outlet, wherein the pump device isadapted to intake fluid through the fluid inlet and to output fluidthrough the fluid outlet; and a fluid seal assembly adapted to permitthe establishment of a pressure differential when the well pump/welldrive plug device is in a well pipe and to permit movement of the wellpump/well drive plug device in the pipe due to the pressuredifferential; wherein the well pump/well drive plug device is adapted tooperate as a well pump when a valve in fluid communication with thefluid inlet and fluid outlet is open to move fluid from the inletthrough the outlet and adapted to operate as a well drive plug devicewhen the valve is closed to enable the formation of the pressuredifferential so that the well pump/well drive plug device may be movedby the pressure differential.
 6. The well pump/well drive plug device ofclaim 5, wherein the pump device is adapted to output fluid to be indirect contact with an interior of the well pipe through which the wellpump/well drive plug device moves.
 7. The well pump/well drive plugdevice of claim 5, wherein the fluid inlet is located on a first side ofthe fluid seal assembly and the fluid outlet is located on a second sideof the fluid seal assembly.
 8. A combination well pump/well drive plugdevice for use in connection with the recovery of hydrocarbonscomprising: a pump device including a fluid inlet and a fluid outlet,wherein the pump device is adapted to intake fluid through the fluidinlet and to output fluid through the fluid outlet; and wherein thecombination well pump/well drive plug device is adapted to convert froma pumping mode to a well drive plug mode to move through a well pipe asa result of a pressure differential.
 9. The combination well pump/welldrive plug device of claim 8, further comprising a valve that, whenopen, permits the fluid inlet to be in fluid communication with thefluid outlet, wherein the combination well pump/well drive plug deviceis adapted to convert from a pump to a drive plug by the closure of thevalve to move through a well pipe as a result of the pressuredifferential enabled by the closure of the valve.
 10. A well,comprising: a combination well pump/well drive plug device according toclaim 9; and a well pipe; wherein the well is adapted to move fluidthrough the combination well pump/well drive plug device and transportthe fluid in the direction of pumping so that the fluid comes intodirect contact with the well pipe.
 11. A well, comprising: a combinationwell pump/well drive plug device according to claim 8; and a well pipe;wherein the well is adapted to move fluid through the combination wellpump/well drive plug device and transport the fluid in the direction ofpumping so that the fluid comes into direct contact with the well pipe.12. A well, comprising: a combination well pump/well drive plug deviceaccording to claim 8, wherein the combination well pump/well drive plugdevice does not have a separate pressure pipe.
 13. A method of pumpingfluid comprising the following actions: (a) placing a combination wellpump/well drive plug device according to claim 8 in a well pipe; (b)converting the combination well pump/well drive plug device to a welldrive plug, wherein action (b) may be performed before or after action(a); forming a pressure difference between a first side and a secondside of the combination well pump/well drive plug device and moving thecombination well pump/well drive plug device through the well pipe bythe pressure difference; and relieving the pressure difference betweenthe first side and the second side of the combination well pump/welldrive plug device; and pumping fluid from the first side to the secondside.
 14. A method of placing a pump in a well pipe comprising: placinga combination well pump/well drive plug device into a well pipe, whereinthe combination well pump/well drive plug device includes a fluid inletand a fluid outlet, wherein the combination well pump/well drive plugdevice is adapted to intake fluid through the fluid inlet and to outputfluid through the fluid outlet when the fluid inlet is in fluidcommunication with the fluid outlet; transporting the combinationwellpump/well drive plug device to a location in the well pipe away fromthe location where the combination well pump/well drive plug device wasplaced into the well pipe utilizing a pressure difference between oneside of a seal on the combination well pump/well drive plug device andanother side of the seal on the combination well pump/well drive plugdevice, the pressure difference being enabled by taking the fluid inletout of fluid communication with the fluid outlet; and opening the valveand pumping fluid from the fluid inlet out the fluid outlet.
 15. Amethod according to claim 14, further comprising using centralizingdevices to keep the pump centered in the well.
 16. A method according toclaim 14, wherein the location is determined by a previously installedstop in the pipe or by a line attached to the well pump/well drive plugdevice.
 17. The method of claim 14, further comprising pumping the fluidthrough the outlet so that the fluid comes into direct contact with thewell pipe.
 18. The method of claim 17, further comprising pumping thefluid towards a surface of the well without the use of a separatepressure pipe.
 19. A method of pumping fluid comprising: forming apressure difference between a first side and a second side of a wellpump device, the first side including a fluid inlet and the second sideincluding a fluid outlet; wherein the well pump device is adapted topump fluid from the fluid inlet through the fluid outlet; transportingthe well pump through a well pipe due to the pressure difference;removing the pressure difference about the well pump device; and pumpingfluid from the fluid inlet through the fluid outlet.
 20. The method ofclaim 19, further comprising pumping the fluid through the outlet sothat the fluid comes into direct contact with the well pipe.
 21. Themethod of claim 19, wherein the pressure difference is formed by takingthe fluid inlet out of fluid communication with the fluid outlet.